Pathogenic Assay of Probiotic Bacteria Producing Proteolytic Enzymes as Bioremediation Bacteria Against Vannamei Shrimp Larvae (Litopenaeus vannamei)

Application of bacteria in bioremediation of shrimp culture ponds is one of the methods used to clean internal pollutants. This study aimed to evaluate the pathogenicity of extracellular proteolytic enzyme produced by the probiotic bacteria as bioremediation bacteria on vannamei shrimp larvae culture. There were five probiotic bacteria, which were successfully isolated from the sediments served as substrate in mangrove area. The isolated bacteria were coded in number as 13, 19, 30, 33, and 36. Pathogenic bacteria Vibrio harveyi was used as positive control. Pathogenic assay was carried out in two different bacterial concentrations, i.e. 10⁸ and 10⁶ cells.mL-1. The results showed that the lowest survival rate (SR) of shrimp larvae in positive control V. harveyi was 53 and 65%. Whereas isolates with the highest SR value (100%) were obtained from bacteria coded as 13 and 30. Isolates no. 19, 33 and 36 had SR of more than 90%. Total plate count (TPC) data showed that the bacteria increased significantly at the end of the study with an average increase value of 24%. The smallest TPC value was shown by bacterial isolate no. 19, while the largest was obtained from the isolate no. 13. These results suggest that all probiotic bacteria were not pathogenic to the vannamei shrimp larvae. Keywords: aquaculture, shrimp, bioremediation, pathogenesis, vibrio.

Enhanced production of extracellular proteolytic enzyme excreted by a newly isolated Bacillus subtilis FBL-1 through combined utilization of statistical designs and response surface methodology

Protease production by newly isolated B. subtilis FBL-1 was optimized and enhanced by combined utilization of three statistical experimental designs.

The urokinase receptor and the regulation of cell proliferation

SummaryThe urokinase receptor is a multifunctional receptor modulating both proteolytic dependent and independent processes. It binds the extracellular proteolytic enzyme urokinase and engages lateral interactions with several transmembrane receptors, including integrins and the EGFR. Both, by initiating a proteolytic cascade acting on the extracellular matrix components, and by regulating the activity of important signal transducers, uPAR participates not only in the modulation of cell-cell and cell-extracellular matrix interactions, but also in the control of extracellular signals determining the proliferative state of a cell. Alteration of such a complex and finely modulated mechanism results in unregulated cell proliferation and altered tissue organization, typically associated with tumor progression.

Biphasic Extracellular Proteolytic Enzyme Activity in Benthic Water and Sediment in the Northwestern Mediterranean Sea

ABSTRACT In this study, we used the fact that bacteria are able to cleave a fluorogenic substrate analog (l-leucine-7-amido-4-methylcoumarin) to determine the maximal ectoproteolytic activities (Vm ) and affinities (Km ) of natural benthic microbial communities by the multiconcentration kinetic method. This investigation was performed during the winter and summer of 1997 with a set of 36 samples of near-bottom water and sediment collected from a coastal area and an offshore area in the western part of the Gulf of Lions. The existence of biphasic microbial ectoproteolysis was statistically confirmed for both the near-bottom water and the sediment, regardless of the spatial and seasonal conditions. Globally, 72.2% of the entire set of bacterial consortia collected at the water-sediment boundary layer showed biphasic microbial kinetics. A specific estimator of the biphasicity indicated that deep benthic bacterial consortia responded better with episodic nutrient supplies than shallower benthic bacterial consortia responded.